1. Technical Field
This invention relates generally to electric water heaters for domestic use. More particularly, this invention relates to a compact electric water heater for domestic uses that is pressureless and continuously self-cleaning. The water heater preferably includes one or more of an automatic fill switch, an inlet temperature sensor block and top-nesting container for mounting tile electric heating element and thermostat.
2. Background Art
The typical electric domestic water heater consists of a steel tank, insulated by fiberglass encased in a metal jacket. Cold water runs into the steel tank, is heated by lower and upper heating elements, and exits through a pipe. As hot water is drained off, cold water mixes with the remaining hot water, reducing the temperature of the remaining water.
Also, in a conventional electric water heater, minerals typically settle out from the water to form sediments, eventually reducing the heater's efficiency and causing corrosion and leaks. In addition, pressure is generated in the tightly sealed tank from heat and from occasional excessive water pressure entering the system from the cold water source. This pressure occasionally results in property damage and personal injury from steam and water leaving the pressure relief valve or from explosion from a failed valve.
The heating elements in conventional electric water heaters often fail before the tank and must be replaced. Because of the design of prior art domestic electric water heaters, replacement of the elements is a difficult task, usually requiring that the water supply be shut off and the tank drained prior to replacing the element.
Conventional electric water heaters are typically constructed of metal, a design that provides for hazardous conditions when a person comes in contact with the unit due to repairs or through casual contact. Conventional electric water heating units may also have electrical wires positioned near the metal surface, which if contacted by a frayed or loose live wire could cause electric shock and significant injury to an individual.